Hello Rob
Firstly, from your qualifications with regards your job you are obviously good enough to make these couplings - no issue. So let's forget that issue. BTW I have had 50 years experience in the hobby and I am not good enough to consider using Jackson couplings on my stock.
Secondly, as Nick says the coupling relies on the vehicles being parallel to the track as the contact are between two mating couplers is so small. Therefore any tendency for a 4 wheel vehicle to be slewed will mean that those couplings will not make contact. Using the Jackson coupling does require precision. S4 wheel standards by definition allow less slop a wagon is far more likely to be "straight and parallel - I don't disagree with Nick, but I still think that S4 standards would be better suited to this coupling. The only layouts I have seen over the years that use Jackson couplings have tended to be S4 - I do not model in S4, I am not promoting S4, I am just saying that the relatively coarse standards used in OO make the job more difficult. Also it is important that the couplings stay well adjusted - it is not a case of "fire and forget" - it is a case of maintaining the couplings in tip top condition.
There are loads of couplings out there for 4mm modelling - and choice of couplings is a very personal one. Often it will depend on whether you are in involved in a group project or to what extent you mix with fellow modellers. If you model in isolation it doesn't matter if you use bent paper clips to join your vehicles as long it suits you. If you are going to work with your friend who uses Alex Jackson then that would be a great plus for you using it too.
Good luck!
Best regards
Paul
